Spark-plug.



' A. E. McDANIEL.

SPARK PLUG.

APPLICATION HLED OCT. 27. l9l5.

I 0 G/ 57/62 Z Patented NOV. 20, 1917.

UNITED s'ra'rns ra'rnn'r OFFKQE. A

v ALBERT ELSWORTI-I MoDANIEL, or CEDAR RAPIDS, town, essre'non. or ONE-HALF ro VALENTINE nuns, or CEDAR RAPIDS, IOWA.

SPARK-PLUG.

Application filed October 27, 1915; Serial No. 58,183. i

To all whom it may concern: Y

Be it known that I, ALBERT E. MCDANIEL, a citizen of the United States, residing at Cedar Rapids, in the'county of Linn and State of Iowa, have invented certain new and useful Improvements in Spark-Plugs, of which the following is a specification.

: This invention relates to the subject of igniters for. internal combustion engines, and more particularly to an improvement in electrical spark plugs.

' As a general object, the invention contemplates a novel and practical spark plug of p the type having a movable terminal element adapted to automatically maintain a proper spark gap for all positionsof the plug. That is to say, it has in view a plug having a movable terminal element'that has a free movement within certain limits about a relatively stationary terminal of opposite polarity, to thus always provide a substantially uniform spark gap, while at the same time preventing the accumulation of dirt of carbon which would otherwise reduce the eflicicncy of the plug. Although this general type of spark plug 'is already known, the practical embodiments thereof are more or less open to structural objections, not only from a practical point of View but from a commercial standpoint.

.Accordingly, the present invention has primarily in view, a simple, substantial, and

reliable construction for self cleaning sparkplugs which will greatlyenhance the practical'value,-*as well as the commercial. In

-this connection; the invention proposes a device hav'ing but few and simple parts which may be readily assembled in theprocessof manufacture, and also readily taken apart 40 when replacements. or repairs are necessary.

A further object of the invention is to provide a spark plug that may be easily and quickly attachedto and removed from the cylinder head of an engine, and which also has all of its parts rigidly connected, so that the danger of any of the parts working loose or falling apart is reduced to a minimum or entirely eliminated, even under the most severe service conditions.

which will more readily appear as the nature of the invention is better understood, the same consists in the novel construction, combination and arrangement of parts herein- WVith the above and other objects in view after more fully described, illustrated and claimed. A preferred and practical embodiment of the invention is illustrated in the accompanying drawings, in which Figure l is an elevation of my improved spark plug.

Fig. 2 is a vertical sectional View thereof.

. Fig. 3 is a detail perspective view of the attaching base thereof.

Fig. 4 is a bottom plan view.

Similar reference characters 'desiggate corresponding parts throughout the several figures of the drawings.

In carrying out the present invention, it is preferred to utilize a plug body which" is formed entirely of one piece,- thus not only facilitating attachment of the plug to the' engine, but at the same time eliminating any separate or unnecessary parts that are likely to become loose. Accordingly, as will be 75. observed from the drawings, the plug body of the invention is generally designated as 1, and has at one end an open sparking cage 2, which is preferably-formed-by making a single cross cut 3 in the rounded end of the plug and a plurality of cross cuts 4 at right angles to the single cross cut 3, thus providing a plurality of spaced ball supporting fingers F. To increase the communication between the inner part of the sparking cage and the interior of the combustion chamber of the engine, the walls 5 of the rounded sparking cage portion may be also provided with the openings 6.

The end of the attaching base opposite the sparking cage 2 is formed with a plurality of external angularly disposed faces 7 which constitute a wrench head whereby the plug may be conveniently fitted to the engine. The exterior portion of the body 1 intermediate the wrench head 7 and the rounded or semi-spherical sparkii'ig cage 2, is pro vided with a plurality of threads 8, which the socket, there is provided a clamping.

ring i l which fits over the shank of the post, as shown in l and is provided with suitable threads for engaging with the threads 10 of the keeper socket. Therefore, it will be clear that the lower edge of this clamping ring will bear against the upper edge of the annular shoulder 13 of the post to lock the latter in place. This clamping ring 1% may be provided with a wrench engaging portion 16 as shown in Fig. l to facilitate the fitting of the same into the keeper socket 9.

The insulating post 12 which is rigidly clamped in the body 1. is provided with a central bore 17 which is adapted to receive an inter ally threaded metallic sleeve 18. This bore 17 flares outwardly at its lower end as indicated at 19 to provide a flared terminal chamber which opens into the sparking cage 2. An adjust-able conductor stem 20 i fitted in the, internally threaded. sleeve l8, and as Till be observed from Fig. 2, the same carries at its "upper end suitable wire terminal clamping nuts 21, While the lower end thereof which extends into the terminal. chamber at the end of the post, is preferably reduced to provides relatively stationary-battery terminal point 22. Ow ing to the mounting of the stem 20 in the sleeve 18, it will be clear that the same may 'be adjusted vertically, that is so that the extremity of the terminal point 22 may be raised and lowered with respect to the bottom of the sparking cage 2. r

The construction above described readily ll S of the self-cleanirrg"feature espeintended to be a characteristic of this sp cage *2 receives a movable terminal ele- 23 which is preferably a smooth metallic ball which has a free and" unobstructed movement throughout the cage, and which is at all times a relatively fixed distance the extremity of the terminal point plug; That is to say,the open sparkto thus provide the desired spark gap.

in the position of parts shown in Fig. 2 the spark will be readily made between the terllLQill end 22 and the ball 23. However,

should the ball 23 for any reason he in contact with the terminal end 22, the spark will then. be made from the ball 23 to the cage 2., whose open construction readily permite ie'nition of the compressed charge in cylinder.

lei-om the foregoing, it is believedto be clearly apparent that the invention provides a spark plug of the self cleaning type which involves a rigid and practical structu n, which although susceptible of being d1 embered when desired, is' absolutely rigid and unitary when in use. This feature together with the practical features of construction constitute a reliable and serviceable plug which effectively ignites thecoinpresscd charge in the cylinder while in any position, andat the same time prevents the accumulation of foreign matter on the sparking terminals. In this connection, it may be noted that the terminal end 22 supplies the current from the battery, while the movable terminal ball 28 which contacts with the metallic cage 2 is the ground terminal, whereby the current makes its wayfrom the battery to the ground through the shank 8 v of the base 1 which fits in the head of the end and an externally threaded holding shank portion, a terminal ballloosely resting on said supporting fingers of the cage, insulating post. locked in said plug body, and an adjustable battery terminal stem carried said post.

In testimony whereof I hereunto aiiix my signature in the presence 20f two witnesses.

ALBERT EliliSvl ORTH MHDANIEL VVit-nesses F, L, GRAHAM, il J. N. vARMsrnorte.

of oppositely Y 

